Method and system for power supply adjustment and polar modulation in a MIMO system

ABSTRACT

Aspects of a method and system for power supply adjustment and polar modulation in a MIMO system are provided. In each RF transmit chain of a MIMO system that utilizes polar modulation, aspects of the invention may enable generating a signal representative of an amplitude of a pair of phase-quadrature baseband signals; and controlling a voltage and/or current regulator utilizing said generated signal. In this regard, a voltage and/or current supplied to a power amplifier and/or mixer of one or more of the transmit chains may be controlled based on the generated signal. Additionally, a gain of a power amplifier for each RF transmit chain may be controlled utilizing said signal representative of an amplitude. The signal representative of an amplitude may be generated by squaring each of the phase-quadrature baseband signals and calculating a square root of a sum of the squared signals.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This patent application makes reference to, claims priority to andclaims benefit from U.S. Provisional Patent Application Ser. No.60/953,100 filed on Jul. 31, 2007.

The above stated application is hereby incorporated herein by referencein its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to signal processing. Morespecifically, certain embodiments of the invention relate to a methodand system for power supply adjustment and polar modulation in a MIMOsystem.

BACKGROUND OF THE INVENTION

Mobile communications have changed the way people communicate and mobilephones have been transformed from a luxury item to an essential part ofevery day life. The use of mobile phones is today dictated by socialsituations, rather than hampered by location or technology. While voiceconnections fulfill the basic need to communicate, and mobile voiceconnections continue to filter even further into the fabric of every daylife, the mobile Internet is the next step in the mobile communicationrevolution. The mobile Internet is poised to become a common source ofeveryday information, and easy, versatile mobile access to this datawill be taken for granted.

As the number of electronic devices enabled for wireline and/or mobilecommunications continues to increase, significant efforts exist withregard to making such devices more power efficient. For example, a largepercentage of communications devices are mobile wireless devices andthus often operate on battery power. Additionally, transmit and/orreceive circuitry within such mobile wireless devices often account fora significant portion of the power consumed within these devices.Moreover, in some conventional communication systems, transmittersand/or receivers are often power inefficient in comparison to otherblocks of the portable communication devices. Accordingly, thesetransmitters and/or receivers have a significant impact on battery lifefor these mobile wireless devices.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for power supply adjustment and polarmodulation in a MIMO system, substantially as shown in and/or describedin connection with at least one of the figures, as set forth morecompletely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 a is a block diagram of a MIMO system, in accordance with anembodiment of the invention.

FIG. 1 b is a block diagram illustrating an exemplary architecture forpolar modulation and control of a power supply based on a signalamplitude in a MIMO system, in accordance with an embodiment of theinvention.

FIG. 1 c is a block diagram illustrating power supply adjustment forpolar modulation of RF signals in a MIMO system.

FIG. 2 a is a flow chart illustrating exemplary steps for controlling again of a power amplifier (PA) for amplitude modulating an output of thePA in a MIMO system, in accordance with an embodiment of the invention

FIG. 2 b is a flow chart illustrating exemplary steps for controlling apower supply to improve transmitter efficiency in a MIMO system, inaccordance with an embodiment of the invention

FIG. 3 is a diagram illustrating exemplary transfer characteristics of aPA for different supply voltages, in accordance with an embodiment ofthe invention.

FIG. 4 is a block diagram illustrating an exemplary MIMO wirelessdevice, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor power supply adjustment and polar modulation in a MIMO system. Ineach RF transmit chain of a MIMO system that utilizes polar modulation,aspects of the invention may enable generating a signal representativeof an amplitude of a pair of phase-quadrature baseband signals; andcontrolling a voltage and/or current regulator utilizing the generatedsignal. In this regard, a voltage and/or current supplied to a poweramplifier and/or mixer of one or more of the transmit chains may becontrolled based on the generated signal. Additionally, a gain of apower amplifier for each RF transmit chain may be controlled utilizingthe signal representative of an amplitude. The signal representative ofan amplitude may be generated by squaring each of the phase-quadraturebaseband signals and calculating a square root of a sum of the squaredsignals.

FIG. 1 a is a block diagram of a MIMO system 100 in accordance with anembodiment of the invention. Referring to FIG. 1 a, the MIMO system 100may comprise one or more RF transmit blocks 102 ₁ . . . , 102 _(Y), oneor more transmit antennas 106 ₁ . . . , 106 _(Y), one or more RF receiveantennas 108 ₁ . . . , 108 _(MN), and one or more RF receive blocks 112₁ . . . , 112 _(M). For example, the system 100 may comprise a number oftransmit blocks Y; and each transmit block may output a signal T, whichmay be transmitted by Y transmit antennas. The system 100 may furthercomprise a number of receive blocks M, which may receive signals fromM×N antennas and each receive block may operate on a number of receivedsignals N and output a data stream D_(i).

The RF transmit blocks 102 ₁ . . . , 102 _(Y) may each comprise suitablelogic, circuitry and/or code that may enable processing of one or moresignals which may then be transmitted. In various embodiments of theinvention, the transmit blocks 102 ₁, . . . , 102 _(Y) perform one ormore of filtering, equalizing, compressing, expanding, up-converting,modulating, amplifying, or otherwise processing signals fortransmission. In this regard, additional details of an exemplarytransmit block may be found in FIG. 1 b.

The transmit antennas 106 ₁ . . . , 106 _(Y) may comprise suitablelogic, circuitry, and/or code that may enable transmission of aplurality of signals in a wireless system. In one embodiment of theinvention, the antennas 106 ₁ . . . , 106 _(Y) may enable transmissionof a plurality of polar modulated signals received from the transmitblocks 102 ₁, . . . , 102 _(Y).

The RF receive blocks 112 ₁ . . . , 112 _(M) may comprise logic,circuitry and/or code that may enable processing of a plurality ofreceived signals. In various embodiments of the invention, the transmitblocks 102 ₁ . . . , 102 _(Y) perform one or more of filtering,equalizing, compressing, expanding, down-converting, de-modulating,amplifying, or otherwise processing signals for reception.

The receive antennas 108 ₁ . . . , 108 _(MN) may comprise suitablelogic, circuitry, and or code that may enable receiving a plurality ofsignals in a wireless system. In one embodiment, the receive antennas108 ₁ . . . , 108 _(MN) may enable reception of a plurality of polarmodulated signals which may be processed by the receive blocks 112 ₁, .. . , 112 _(M).

FIG. 1 b is a block diagram illustrating an exemplary architecture forcontrolling a power supply and polar modulating a signal in a MIMOsystem, in accordance with an embodiment of the invention. Referring toFIG. lb there is shown at least a portion of an RF transmitter 102comprising two pulse shaping circuits 122 a and 122 b, amplitudecalculation block 124, division blocks 126 a and 126 b, mixers 128 a and128 b, a summing circuit 130, and power amplifier (PA) 132.

The pulse shaping circuits 122 a and 122 b may comprise suitable logic,circuitry, and/or code that may enable filtering, equalizing,compressing, or otherwise processing and/or conditioning the signalsI(t) and Q(t), respectively. In various embodiments of the invention,the pulse shaping may occur before or after calculating A(t).

The amplitude calculation block 124 may comprise suitable logic,circuitry, and/or code that may enable performing the followingcalculation:A(t)=√{square root over (I ²(t)+Q ²(t))}{square root over (I ²(t)+Q²(t))}  EQ. 1where I(t) and Q(t) are in-phase and quadrature-phase, respectively,components of an input baseband signal and A(t) represents an amplitudecomponent of a polar modulated signal. In various embodiments of theinvention, the calculation may be carried out in the analog domain, thedigital domain, or a combination thereof. In various embodiments of theinvention, the amplitude calculation block 124 may comprise one or moreprocessors or may be implemented in one or more processors. In variousembodiments of the invention, the amplitude calculation block mayoperate on I and Q before or after pulse shaping has been performed on Iand Q.

The division blocks 126 a and 126 b may comprise suitable logic,circuitry, and/or code that may enable dividing one baseband signal byanother. In various embodiments of the invention, the calculation may becarried out in the analog domain, the digital domain, or a combinationthereof. In various embodiments of the invention, the amplitudecalculation block 124 may comprise one or more processors or may beimplemented in one or more processors.

The mixers 128 a and 128 b may comprise suitable logic, circuitry,and/or code that may enable generation of inter-modulation productsresulting from the mixing of a baseband signal and a RF carrier from,for example, a local oscillator. The mixer 128 a may, for example, beenabled to utilize an in-phase carrier signal to generate in-phaseinter-modulation products. The mixer 128 b may, for example, be enabledto utilize a quadrature phase LO signal to generate quadrature phaseinter-modulation products. The frequency of the carrier signals may bedetermined based on the desired radio frequency for transmission. Inthis regard, the mixers 128 a and 128 b may enable up-converting, forexample, baseband signals of a fixed frequency to a variable radiofrequency for transmission. In various embodiments of the invention, avoltage and/or current regulator 134 supplying the mixers 128 a and/or128 b may be modified based on the amplitude signal. In this manner,linearity requirements and/or efficiency of the system may be improved.

The summing circuit 130 may comprise suitable logic, circuitry, and/orcode that may enable adding an in-phase component and a quadrature-phasecomponent to generate a phase modulated RF signal. In variousembodiments of the invention, the calculation may be carried out in theanalog domain, the digital domain, or a combination thereof. In variousembodiments of the invention, the summing circuit 130 may comprise oneor more processors or may be implemented in one or more processors.

The power amplifier (PA) 132 may comprise suitable logic, circuitry,and/or code that may enable buffering and/or amplification of a RFsignal and outputting the signal to an antenna for transmission. In thisregard, the gain of the PA 132 may be adjustable and may enabletransmitting signals of varying strength. Accordingly, the PA 132 mayenable amplitude modulating an RF signal input to the PA 132. In thisregard, a bias point or other adjustable parameter of the PA 132 may becontrolled to vary the gain of the PA 132 resulting in amplitudemodulation of the PA 132 output. Additionally, a voltage and/or currentregulator 134 supplying the PA 132 may be modified based on theamplitude signal. In this manner, linearity requirements and/orefficiency of the system may be improved as described, for example, withrespect to FIG. 3.

The voltage and/or current regulator 134 may comprise suitable logiccircuitry, and/or code that may be a power source to one or more of themixers 128 a, 128 b, and the PA 132. Additionally, the voltage and/orcurrent regulator 134 may enable altering a voltage and/or current itsupplies based on an input signal. In this regard, the voltage and/orcurrent regulator 134 may adjust a voltage and/or current supplied tothe mixers 128 a and 128 b, and/or the PA 132, based on the amplitudesignal from the amplitude calculation block 124. In one embodiment ofthe invention, the output voltage and/or current of the voltage and/orcurrent regulator 134 may scale linearly with A(t).

In operation, a baseband signal may be split into in-phase, I(t), andquadrature-phase Q(t), components. The signal components may be conveyedto the pulse shaping circuits 122 a and 122 b, respectively.Additionally, I(t) and Q(t) may be conveyed to the amplitude calculationblock 124 where A(t) may be generated. The output of the pulse shapingblocks 122 a and 122 b may, respectively, be conveyed to the divisionblocks 126 a and 126 b. The division blocks 126 a and 126 b may divideI(t) and Q(t) by A(t) to generate I′(t) and Q′(t). I′(t) and Q′(t) may,respectively, be mixed with in-phase and quadrature-phase components ofan RF carrier signal. The outputs of the mixers may then be summed togenerate a carrier signal phase modulated by the baseband signal. Thephase modulated signal may be conveyed to the PA 132. The gain of the PA132 may be controlled to amplitude modulate the signal output by the PA132. Accordingly, the signals transmitted by the PA 132 may comprise aRF carrier polar modulated by the baseband signal. Additionally, thevoltage and/or current regulator 134 may scale the voltage and/orcurrent supplied to the mixers 128 a, 128 b, and/or the PA 132 based onthe output of the amplitude calculation block 124. For example, when thesignal from the amplitude calculation block is relatively small, avoltage and/or current supplied by the voltage and/or current regulator134 may be reduced. Similarly, when the signal from the amplitudecalculation block is relatively large, a voltage and/or current suppliedby the voltage and/or current regulator 134 may be increased.

FIG. 1 c is a block diagram illustrating power supply adjustment forpolar modulation of RF signals in a MIMO system. Referring to FIG. 1 cthere is shown a portion of n RF transmit chains 102 ₁, . . . , 102_(n). Each of the n RF transmit chains 102 ₁, . . . , 102 _(n) maycomprise mixers 128 a _(i) and 128 b _(i) for in-phase andquadrature-phase components, a summer 130 _(i), a power amplifier (PA)132 _(i), and one or more voltage and/or current regulators 134 _(i).

An in-phase baseband signal may be coupled to a first input of eachmixer 128 a _(i), and a quadrature-phase component may be coupled to afirst input of each mixer 128 b _(i). An in-phase LO signal may becoupled to a second input of each mixer 128 a _(i), and aquadrature-phase LO signal may be coupled to a second input of eachmixer 128 b _(i). The output of each mixer 128 a _(i) and 128 b _(i) maybe coupled to an input of the summer 130 _(i). The output of the summer130 _(i) may be coupled to an input of the PA 132 _(i). Each mixer 128 a_(i) and 128 b _(i) and each PA 132 _(i) may be coupled to a voltageand/or current regulator 134 _(i), which, in turn, may be coupled to anamplitude calculation block, such as the amplitude calculation block 124described with respect to FIG. 1 b.

In operation, a baseband signal to be transmitted via a transmit chain102 _(i) may be split into in-phase, I(t), and quadrature-phase Q(t),components. The signal components may be conditioned, for example, byone or more pulse shaping circuits. Additionally, an amplitudecomponent, A_(i), of a polar representation of the baseband signal maybe calculated. Moreover, the components I(t)_(i) and Q(t)_(i) may bedivided by A_(i), up-converted, and subsequently combined to generate asignal representative of a phase portion of a polar representation ofthe baseband signal. The signal representative of a phase may be inputto a PA 132 _(i) for amplification. Additionally, the output of the PA132 _(i) may be amplitude modulated such that the transmitted signal,S_(i), may be a carrier that is polar modulated by the input basebandsignal. Accordingly, the signal transmitted by each PA 132 _(i) maycomprise a RF carrier polar modulated by the baseband signal. In variousembodiments of the invention, the voltage and/or current regulator block134 _(i) may be adjusted based on the signal A_(i). For example, thesupply voltage of PA 132 _(i) may scale linearly with the signal A suchthat _(S) _(i) is amplitude modulated by A_(i) or a signal proportionalto A_(i).

FIG. 2 a is a flow chart illustrating exemplary steps for controlling again of a PA for amplitude modulating an output of the PA in a MIMOsystem, in accordance with an embodiment of the invention. Referring toFIG. 2 a, the exemplary steps may begin with start step 202. Subsequentto step 202, the exemplary steps may advance to step 204. In step 204, asignal, A_(i), representative of the amplitude of a pair of phasequadrature baseband signals I_(i) and Q_(i) may be generated for eachtransmit chain 102 _(i) in a MIMO transmitter. In this regard, EQ. 1above may be utilized to generate the each amplitude signal. Subsequentto step 204, the exemplary steps may advance to step 206. In step 206,the signals I_(i) and Q_(i) may be processed by a pulse shaping block.For example, each of the signals I_(i) and Q_(i) may be filtered,equalized, and/or compressed. Subsequent to step 206, the exemplarysteps may advance to step 208. In step 208, the signals I_(i) and Q_(i)may each be divided by the amplitude signal A_(i) generated in step 204,resulting in signals, I′_(i) and Q′_(i). Subsequent to step 208, theexemplary steps may advance to step 210. In step 210, the signals I′ andQ′ may be mixed with in-phase and quadrature-phase LO signals,respectively, to up-convert the signals to RF. In various embodiments ofthe invention, each transmit chain 102 _(i) may utilize LO signals withdifferent frequencies and/or phases. Subsequent to step 210, theexemplary steps may advance to step 212. In step 212, the up-convertedsignals of each transmit chain 102 _(i) may be combined to generate aphase modulated RF signal for each transmit chain 102 _(i). Subsequentto step 212, the exemplary steps may advance to step 214. In step 214,each phase modulated signal resulting from step 212 may be amplified fortransmission by the power amplifier 132 _(i). Moreover, the gain of eachamplifier 132 _(i) may be controlled, based on the amplitude signalgenerated in step 204, to amplitude modulate the output of the PA 132_(i). In this manner, a polar modulated signal may be generated by eachtransmit chain 102 _(i) comprising a MIMO wireless device.

FIG. 2 b is a flow chart illustrating exemplary steps for controlling apower supply to improve transmitter efficiency in a MIMO system, inaccordance with an embodiment of the invention. Referring to FIG. 2 b,the exemplary steps may begin with start step 222. Subsequent to step222, the exemplary steps may advance to step 224. In step 224, a signal,A_(i), representative of the amplitude of the signals I_(i) and Q_(i)may be generated for each transmit chain 102 _(i) in a MIMO wirelessdevice. In this regard, EQ. 1 above may be utilized to generate eachamplitude signal. Subsequent to step 224, the exemplary steps mayadvance to step 226. In step 226, a voltage and/or current supplying apower amplifier and/or mixers of each transmit chain 102 _(i) may beadjusted based on the amplitude of A_(i). For example, a supply voltageto the PA 132 _(i) may be increased when the amplitude is relatively lowand the supply voltage to the PA 132 _(i) may be increased when theamplitude is relatively high. In this manner, efficiency of the PA 132_(i) may be improved over conventional methods and systems as, forexample, described with respect to FIG. 3.

FIG. 3 is a diagram illustrating exemplary transfer characteristics of aPA for different supply voltages, in accordance with an embodiment ofthe invention. Referring to FIG. 3 there is shown a PA transfercharacteristic 302 and 1 dB compression point 306 corresponding to ahigher supply voltage, a PA transfer characteristic 304 and 1 dBcompression point 310 corresponding to a lower supply voltage, anoperating point 308 corresponding to higher PA output levels, and anoperating point 312 corresponding to lower PA output levels.

In operation, if a PA is always powered with a higher supply voltage,then the transfer characteristic of the PA may always be thecharacteristic 302. Accordingly, when the output levels of the PA arearound point 312, the PA will be significantly less power efficient,than when output levels of the PA are around the point 308. In thisregard, a determinant of PA efficiency may be the difference between theoperating point and the 1 dB compression point. Accordingly, anoperating point closer to the 1 db compression point may equate toimproved power efficiency. For example, the difference 316 a betweenpoints 306 and 312 may be significantly greater than the difference 314between points 306 and 308. Accordingly, when operating around the point312, reducing the supply voltage of the PA such that the 1 dBcompression point is moved to the point 310, then the efficiency of thePA may be improved. In this regard, the distance 316 b between thepoints 310 and 312 may be significantly less than the distance 316 a.Accordingly, in a MIMO system, components of each transmit chain 120_(i) may be operated at a voltage and/or current level that increasespower efficiency for that chain. In this manner, overall efficiency of aMIMO wireless device may be improved by separately controlling voltageand/or current levels for each transmit chain.

FIG. 4 is a block diagram illustrating an exemplary MIMO wirelessdevice, in accordance with an embodiment of the invention. Referring toFIG. 4, there is shown a wireless device 420 that may comprise an RFreceiver 423 a, an RF transmitter 423 b, a digital baseband processor429, a processor 425, and a memory 427. Receive antennas 408 ₁, . . . ,408 _(MN) may be communicatively coupled to the RF receiver 423 a.Transmit antennas 406 ₁, . . . , 406 _(Y) may be communicatively coupledto the RF transmitter 423 b. The wireless device 420 may be operated ina system, such as a cellular network and/or digital video broadcastnetwork, for example.

The RF receiver 423 a may comprise suitable logic, circuitry, and/orcode that may enable processing of received RF signals. The RF receiver423 a may enable receiving RF signals in a plurality of frequency bands.For example, the RF receiver 423 a may enable receiving signals incellular frequency bands. Each frequency band supported by the RFreceiver 423 a may have a corresponding front-end circuit for handlinglow noise amplification and down conversion operations, for example. Inthis regard, the RF receiver 423 a may be referred to as a multi-bandreceiver when it supports more than one frequency band. In anotherembodiment of the invention, the wireless device 420 may comprise morethan one RF receiver 423 a, wherein each of the RF receivers 423 a maybe a single-band or a multi-band receiver. In this regard, the receiver423 a may comprise the receive blocks 112 ₁, . . . , 112 _(M), which aredescribed with respect to FIG. 1.

The RF receiver 423 a may down convert the received RF signal to abaseband signal that comprises an in-phase (I) component and aquadrature (Q) component. The RF receiver 423 a may perform direct downconversion of the received RF signal to a baseband signal, for example.In some instances, the RF receiver 423 a may enable analog-to-digitalconversion of the baseband signal components before transferring thecomponents to the digital baseband processor 429. In other instances,the RF receiver 423 a may transfer the baseband signal components inanalog form.

The digital baseband processor 429 may comprise suitable logic,circuitry, and/or code that may enable processing and/or handling ofbaseband signals. In this regard, the digital baseband processor 429 mayprocess or handle signals received from the RF receiver 423 a and/orsignals to be transferred to the RF transmitter 423 b, when the RFtransmitter 423 b is present, for transmission to the network. Thedigital baseband processor 429 may also provide control and/or feedbackinformation to the RF receiver 423 a and to the RF transmitter 423 bbased on information from the processed signals. In this regard, thebaseband processor may provide a control signal to one or more of thepulse shaping blocks 122 a and 122 b, the amplitude calculation block124, the division blocks 126 a and 126 b, the mixers 128 a and 128 b,voltage and/or current regulator 134, the summer 130, and/or the PA 132.The digital baseband processor 429 may communicate information and/ordata from the processed signals to the processor 425 and/or to thememory 427. Moreover, the digital baseband processor 429 may receiveinformation from the processor 425 and/or to the memory 427, which maybe processed and transferred to the RF transmitter 423 b fortransmission to the network.

The RF transmitter 423 b may comprise suitable logic, circuitry, and/orcode that may enable processing of RF signals for transmission. The RFtransmitter 423 b may enable transmission of RF signals in a pluralityof frequency bands. For example, the RF transmitter 423 b may enabletransmitting signals in cellular frequency bands. Each frequency bandsupported by the RF transmitter 423 b may have a corresponding front-endcircuit for handling amplification and up conversion operations, forexample. In this regard, the RF transmitter 423 b may be referred to asa multi-band transmitter when it supports more than one frequency band.In another embodiment of the invention, the wireless device 420 maycomprise more than one RF transmitter 423 b, wherein each of the RFtransmitter 423 b may be a single-band or a multi-band transmitter. Inthis regard, the receiver 423 a may comprise a plurality of the transmitblocks 102 ₁, . . . , 102 _(Y), which are described with respect to FIG.1.

The RF transmitter 423 b may quadrature up convert the baseband signalcomprising I/Q components to an RF signal. The RF transmitter 423 b mayperform direct up conversion of the baseband signal to a RF signal, forexample. The RF transmitter may be enabled to polar modulate one or morecarrier signals by the baseband signal. Accordingly, the RF transmitter423 b may comprise a plurality of transmit chains, such as the transmitchains 120 ₁, . . . , 120 _(n) described with respect to FIG. 1 c. Inthis regard, the RF transmitter may be enabled to separate thegeneration of phase and amplitude components of a signal to betransmitted. In this manner, the RF transmitter may be enabled toperform phase modulation independent of amplitude modulation. Forexample, the output of the summers 130 ₁, . . . , 130 _(n), as describedwith respect to FIGS. 1 c, may comprise phase modulated signals whichare subsequently amplitude modulated by controlling a gain of the poweramplifiers 132 ₁, . . . , 132 _(n). Moreover, power efficiency of the RFtransmitter 423 b may be improved by controlling one or more voltagesand/or currents supplied to components of one or more of the transmitchains 120 ₁, . . . , 120 _(n), as described with respect to FIG. 1 c.In some instances, the RF transmitter 423 b may enable digital-to-analogconversion of the baseband signal components received from the digitalbaseband processor 429 before up conversion. In other instances, the RFtransmitter 423 b may receive baseband signal components in analog form.

The processor 425 may comprise suitable logic, circuitry, and/or codethat may enable control and/or data processing operations for thewireless device 420. The processor 425 may be utilized to control atleast a portion of the RF receiver 423 a, the RF transmitter 423 b, thedigital baseband processor 429, and/or the memory 427. In this regard,the processor 425 may generate at least one signal for controllingoperations within the wireless device 420. In this regard, the basebandprocessor may provide a control signal to one or more of the pulseshaping blocks 122 a and 122 b, the amplitude calculation block 124, thedivision blocks 126 a and 126 b, the mixers 128 a and 128 b, voltageand/or current regulator 134, the summer 130, and/or the PA 132. Theprocessor 425 may also enable executing of applications that may beutilized by the wireless device 420. For example, the processor 425 mayexecute applications that may enable displaying and/or interacting withcontent received via cellular transmission signals in the wirelessdevice 420.

The memory 427 may comprise suitable logic, circuitry, and/or code thatmay enable storage of data and/or other information utilized by thewireless device 420. For example, the memory 427 may be utilized forstoring processed data generated by the digital baseband processor 429and/or the processor 425. The memory 427 may also be utilized to storeinformation, such as configuration information, that may be utilized tocontrol the operation of at least one block in the wireless device 420.For example, the memory 427 may comprise information necessary toconfigure the RF receiver 423 a to enable receiving cellulartransmission in the appropriate frequency band. In this regard, thebaseband processor may store control and/or configuration informationfor one or more of the pulse shaping blocks 122 a and 122 b, theamplitude calculation block 124, the division blocks 126 a and 126 b,the mixers 128 a and 128 b, voltage and/or current regulator 134, thesummer 130, and/or the PA 132.

Aspects of a method and system for power supply adjustment and polarmodulation in a MIMO system are provided. In each RF transmit chain 102_(i) of a MIMO system that utilizes polar modulation, such as the MIMOwireless device described with respect to FIG. 4, aspects of theinvention may enable generating a signal, A_(i), representative of anamplitude of a pair of phase-quadrature baseband signals; andcontrolling a voltage and/or current regulator 134 _(i) utilizing saidgenerated signal. In this regard, a voltage and/or current supplied to apower amplifier 132 _(i) and/or mixers 128 a _(i) and 128 b _(i), of oneor more of the transmit chains 102 _(i) may be controlled based on thegenerated signal. Additionally, a gain of a power amplifier for saideach RF transmit chain may be controlled utilizing said signalrepresentative of an amplitude, to enable amplitude modulating theoutput of the PA. The signal representative of an amplitude may begenerated by squaring each of the phase-quadrature baseband signals andcalculating a square root of a sum of the squared signals.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described herein for power supply adjustment andpolar modulation in a MIMO system.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method for signal processing, the methodcomprising: in each radio frequency (RF) transmit chain of a multipleinput multiple output (MIMO) system that utilizes polar modulationgenerating a signal representative of an amplitude of a pair ofphase-quadrature baseband signals by squaring each of said pair ofphase-quadrature baseband signals and calculating a square root of a sumof said pair of squared phase-quadrature baseband signals; dividing eachof said pair of phase-quadrature baseband signals by said signalrepresentative of said amplitude; controlling a supply voltage or asupply current generated by a voltage regulator or a current regulator,said supply voltage or said supply current being linearly proportionalto the square root of the sum of the pair of squared phase-quadraturebaseband signals; and modifying a 1 dB compression point of an amplifierof said RF transmit chain of said MIMO system according to the supplyvoltage or the supply current linearly proportional to the square rootof the sum of the pair of squared phase-quadrature baseband signals. 2.The method according to claim 1, wherein said signal representative ofsaid amplitude is generated before or after pulse shaping said pair ofphase-quadrature baseband signals.
 3. The method according to claim 1,wherein the modifying is performed such that the 1 dB compression pointof the amplifier is moved closer to an operating point of an amplifier.4. A non-transitory machine-readable storage having stored thereon, acomputer program having at least one code section for signal processing,the at least one code section being executable by a machine for causingthe machine to perform a method comprising: in each radio frequency (RF)transmit chain of a multiple input multiple output (MIMO) system thatutilizes polar modulation generating a signal representative of anamplitude of a pair of phase-quadrature baseband signals by squaringeach of said pair of phase-quadrature baseband signals and calculating asquare root of a sum of said pair of squared phase-quadrature basebandsignals; dividing each of said pair of phase-quadrature baseband signalsby said signal representative of said amplitude; controlling a supplyvoltage or a supply current generated by a voltage regulator or acurrent regulator, said supply voltage or said supply current beinglinearly proportional to the square root of the sum of the pair ofsquared phase-quadrature baseband signals; and modifying a 1 dBcompression point of an amplifier of said RF transmit chain of said MIMOsystem according to the supply voltage or the supply current linearlyproportional to the square root of the sum of the pair of squaredphase-quadrature baseband signals.
 5. The non-transitorymachine-readable storage according to claim 4, wherein said signalrepresentative of said amplitude is generated before or after pulseshaping said pair of phase-quadrature baseband signals.
 6. Thenon-transitory machine-readable storage according to claim 4, whereinthe modifying is performed such that the 1 dB compression point of theamplifier is moved closer to an operating point of the amplifier.
 7. Asystem for signal processing, the system comprising: one or morecircuits in each radio frequency (RF) transmit chain of a multiple inputmultiple output (MIMO) system that utilizes polar modulation, said oneor more circuits operate to generate a signal representative of anamplitude of a pair of phase-quadrature baseband signals by squaringeach of said pair of phase-quadrature baseband signals and calculating asquare root of a sum of said pair of squared phase-quadrature basebandsignals; divide each of said pair of phase-quadrature baseband signalsby said signal representative of said amplitude; control a supplyvoltage or a supply current generated by a voltage regulator or acurrent regulator, said supply voltage or said supply current beinglinearly proportional to the square root of the sum of the pair ofsquared phase-quadrature baseband signals; and modify a 1 dB compressionpoint of an amplifier of said RF transmit chain of said MIMO systemaccording to the supply voltage or the supply current linearlyproportional to the square root of the sum of the pair of squaredphase-quadrature baseband signals.
 8. The system according to claim 7,wherein said one or more circuits comprise a pulse shaping circuit, andwherein said signal representative of said amplitude of said pair ofphase-quadrature baseband signals is generated before or after pulseshaping said pair of phase-quadrature baseband signals.
 9. The systemaccording to claim 7, wherein a first supply voltage is supplied topower the amplifier and a second supply voltage is supplied to power amixer of one or more mixers.
 10. The system according to claim 7,wherein the one or more circuits in each RF transmit chain modify the 1dB compression point such that the 1 dB compression point of theamplifier is moved closer to an operating point of the amplifier.